Add masscan+nuclei mode, operator tuning controls, and vars file support to webrunner

- New scan mode: masscan+nuclei — masscan finds open ip:port pairs,
  nuclei runs operator-supplied CVE template against discovered hosts
- Per-country vulnerable host count in merge output via CIDR→country lookup
- Tuning args on every scan: --nmap-timing, --nmap-timeout, --nmap-workers,
  --nuclei-rate, --nuclei-concurrency, --nuclei-timeout, --masscan-rate
- Vars file support: operator provides scan_vars.yaml to pre-fill all
  tuning settings without interactive prompts
- Templates copied to nodes at provision time — no live fetches (OPSEC)
- run_scan.yml passes all tuning args with Ansible defaults as fallback
- configure_node.yml installs nuclei binary + uploads template on demand
- Updated deployment summary shows mode-specific tuning params
- countries-format.md and targets-format.md updated for new capabilities
- scan_vars.yaml.example documents all configurable settings with comments

utils/provider_rates.py

@@ -22,10 +22,11 @@ INSTANCE_RATES = {
 }
 
 SCAN_MODES = {
-    'geo-scout':    {'rate': 3000,  'desc': 'masscan + nmap + probe fingerprinting'},
-    'masscan-only': {'rate': 10000, 'desc': 'masscan port discovery only'},
-    'nmap-only':    {'rate': 500,   'desc': 'nmap full fingerprint only'},
-    'masscan+nmap': {'rate': 5000,  'desc': 'masscan + nmap (no probes)'},
+    'geo-scout':      {'rate': 3000,  'desc': 'masscan + nmap + probe fingerprinting'},
+    'masscan-only':   {'rate': 10000, 'desc': 'masscan port discovery only'},
+    'nmap-only':      {'rate': 500,   'desc': 'nmap full fingerprint only'},
+    'masscan+nmap':   {'rate': 5000,  'desc': 'masscan + nmap (no probes)'},
+    'masscan+nuclei': {'rate': 5000,  'desc': 'masscan discovery + nuclei CVE template'},
 }
 
 PRESETS = {